1. Field of the Invention
The present invention relates to a display device, and more particularly, to a light emission device for emitting light using electron emission regions and a phosphor layer, and a display device using the light emission device as a light source.
2. Description of Related Art
A light emission device that includes front and rear substrates facing each other with a gap therebetween, a plurality of electron emission regions provided on the rear substrate, and a phosphor layer and an anode electrode provided on the front substrate is well known. The light emission device has a simplified optical member and lower power consumption than both a cold cathode fluorescent lamp (CCFL) type light emission device and a light emitting diode (LED) type light emission device.
The rear and front substrates are sealed together at their peripheries using a sealing member to form a vacuum vessel. In the light emission device, electrons emitted from the electron emission regions are accelerated toward the phosphor layer by an anode voltage applied to the anode electrode, and excite the phosphor layer to emit visible light. The luminance of a light emission surface is proportional to the anode voltage.
The light emission device can be used as a light source in a display device including a non-self emissive type display panel. In the light emission device, a large amount of heat is generated from the front substrate by the continuous electron collision with the phosphor layer. However, since the front substrate is disposed facing the display panel, it is very difficult to install a cooling device. Therefore, the heat generated from the front substrate causes the deterioration of not only the performance of the display panel but also of the light emission efficiency of the phosphor layer that is exposed to the heat for a long time.
In addition, the light emission device is driven so as to maintain a predetermined brightness all the entire light emission surface when the display device is driven. Therefore, it is difficult to improve the display quality to a sufficient level.
Therefore, it is desirable to provide a light emission device that can overcome the shortcomings of the conventional light emission devices to better dissipate heat and/or to improve the dynamic contrast of the image displayed by the display device.